Molecular Phylogeny and New Haplotypes of Extinct Asian Black Bear Populations in Kyushu Island, Japan

Abstract

　Asian black bears (Ursus thibetanus) in Japan are clustered into 3 lineages (eastern, western, and southern clusters) based on mitochondrial DNA (mtDNA) haplotypes of an approximately 700 bp sequence in the D-loop region of mtDNA. In 2012 the Ministry of the Environment of Japan announced the Asian black bear population in Kyushu, the southwestern island of the Japanese archipelago, as locally extinct, because the last reliable record of the Asian black bear in Kyushu was in 1941. The number of samples and genetic analysis results pertaining to the Asian black bear population in Kyushu are very few. Therefore, the molecular phylogenetic characteristics of Asian black bears in Kyushu remain a missing link in understanding the trajectory of Asian black bear populations from the Asian mainland to Japan. In this study, we investigated the mtDNA haplotypes of Asian black bears in Kyushu using four old bone samples, which we found at various locations and dates. We succeeded in detecting two new haplotypes and a haplotype of the western cluster. The two new haplotypes also belonged to the western cluster. These results suggest a continuous distribution of Asian black bears between western Chugoku and Kyushu, and indicate that genetic variation occurred after habitat fragmentation. These results provide data to support the considerations of previous studies on the migration of Asian black bears from the Asian continent to the Japanese archipelago.